[RFC PATCH v2 1/4] arm64: defconfig: increase NR_CPUS range to 2-128

Ganapatrao Kulkarni
2014-12-24T12:33:44Z

On Tue, Dec 9, 2014 at 1:57 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Monday 08 December 2014 17:57:03 Zi Shen Lim wrote:
>> Hi Arnd,
>>
>> On Mon, Nov 24, 2014 at 3:53 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>> >
>> > On Saturday 22 November 2014 02:53:27 Ganapatrao Kulkarni wrote:
>> > > Raising the maximum limit to 128. This is needed for Cavium's
>> > > Thunder system that will have 96 cores on Multi-node system.
>> > >
>> > > Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@caviumnetworks.com>
>> > >
>> >
>> > Could we please raise the compile-time limit to the highest number that
>> > you are able to boot successfully on some existing machine?
>> >
>> > There isn't much point in doubling this every few months.
>>
>> Agreed. If we look back at [1], Mark Rutland has actually compiled and
>> boot-tested NR_CPUS=4096 on Juno.
>>
>> [1] https://lkml.org/lkml/2014/9/8/537
>
> Ok, 4096 sounds like a good NR_CPUS limit then, it should last for a while.
Ok, will set range to 2-4096.
>
> For the defconfig, we probably want a much smaller value, either one that
> covers all known machines (96 at this time), or something that covers
> 95% of all users (maybe 32?) and does not have an serious impact on
> memory consumption or performance on small machines.
>
> Arnd
thanks
Ganapat